1. Field of the Invention
This invention pertains to fluid control devices in general, and in particular, to a form of fast-acting, electromagnetic solenoid valve.
2. Description of the Related Art
Electromagnetically actuated solenoid or relay valves have fairly widespread application in the field of fluidics and fluid control, wherein their speed of operation and precise controllability are important factors. Examples of such use are the fuel injector valves used in modern internal combustion engines and the fuel control valves used in liquid rocket engines.
One known type of such valve employs a bipolar electromagnet to selectably pull a moveable magnetic armature or valve element, such as a ferrous poppet plate, through an air gap or stroke and away from its position of normally biased engagement with a static valve seat to open the valve and initiate flow. An example of this type of valve structure may be seen in U.S. Pat. No. 2,321,853 to W. A. Ray.
In such valve types, fluid flow response time is a function of, among other things, the length of the poppet stroke. As a first approximation, longer stroke lengths result in larger flows but slower actuation times, and vice-versa. Over the years, efforts have been made to derive faster-acting valves which still retain relatively large flow characteristics.
One such effort is that of H. Knapp, et al., described in U.S. Pat. No. 4,365,747, in which the armature carries a valve element acting in cooperation with a fixed, centrally located valve seat, and is guided into seating engagement by a guide diaphragm made of non-magnetic material attached to its outer circumference, which is said to prevent magnetic adhesion of the armature.
In U.S. Pat. No. 4,390,130, M. Linssen, et al., disclose a similar arrangement in which a ball element is attached to the center of a flat armature which, in turn, is pivotally attached at its side by a spring tongue, thereby resulting in an unequivocal up-or-down movement of the armature.
In U.S. Pat. No. 4,572,436, E. Stettner, et al., disclose such a valve in which the armature valve plate is tapered on its top, or solenoid-facing surface to create a wedge-shaped air gap between it and the solenoid. The valve plate is retained both radially and axially by a special retainer clip to move pivotally about a peripheral edge into, and out of, engagement with orifices contained within a valve seat.
It will be seen that such pivoting-armature arrangements can result in a relatively larger axial movement of the armature plate in the vicinity of the valve seat for a given mean, or average, armature stroke, or alternatively, a faster opening response for a given effective armature displacement, either one a desirable result. However, these prior executions of this concept have been hindered by the necessity of some artifice to maintain a precise, fixed angular relationship between the valve plate and the seat, such as the alignment springs, clips, balls, pins or the like discussed in these references. The latter elements result in increased manufacturing costs, increased complexity, and reduced reliability in this type of valve.
It is therefore desirable to provide an electromagnetic solenoid valve of the type discussed hereinabove which affords faster response times and/or larger armature displacements in the vicinity of the valve seat for a given mean poppet displacement, while eliminating the necessity for the precise and complex valve member and seat aligning means of the prior art.